RESEARCH ARTICLE Design of wideband AMC integrated monopole antenna with enhanced radiation performances for off-body systems Bidisha Hazarika | Banani Basu | Arnab Nandi Department of Electronics and Communication Engineering, National Institute of Technology Silchar, Silchar, Assam, India Correspondence Banani Basu, Department of Electronics and Communication Engineering, National Institute of Technology Silchar, Silchar, 788010 Assam, India. Email: banani.basu@gmail.com Abstract A low-profile, wideband, high gain artificial magnetic conductor (AMC) integrated monopole antenna is pro- posed in the letter. The bowl-shaped stair styled mono- pole with defected round type partial ground is integrated with the AMC containing 2 × 2 unit-cells to broaden the impedance bandwidth by 92.7%/66.2%/53.9% at the three resonating notches at 6/8.4/10.3 GHz respectively. The AMC has covered 90  reflection phase bandwidth from 6.20 to 7.44 GHz (18.56%). The planar AMC prof- fers mu-negative (MNG) properties and polarization independent behavior. Introduction of AMC beneath the monopole achieves wideband from 5.39 to 10.95 GHz. The AMC integrated monopole provides peak gain up to 10.6 dB which is 66.8% better than that of the only monopole. The integrated antenna offers low-profile fea- tures with unidirectional radiation behavior, up to 18.6 dB front to back ratio (FBR) and >90% efficiency. The proposed design reduces 1-g averaged Specific Absorption Rate (SAR) at 1 mm distance up to 96.6% at the respective bands. KEYWORDS artificial magnetic conductor (AMC), specific absorption rate (SAR), unit-cell, wideband antenna 1 | INTRODUCTION Recent development of communication system demands the improvement of planar antenna performance related to the multiband operation with wide impedance bandwidth and compactness. Narrow operational bandwidth, low gain and excitation of surface wave eventually lower the radiation efficiency of an antenna. In recent times, artificial magnetic conductor (AMC) has been utilized to enhance the band- width and gain of the planar antennas in References 1-7. In Reference 1, a low-profile multiband AMC antenna with better radiation performances has been proposed. Low- profile AMC loaded antenna with wide bandwidth and high gain has been reported in References 2 and 3. An implant- able antenna with 12.2% impedance bandwidth and reduced SAR is presented in Reference 4. A slotted AMC based antenna with wide impedance bandwidth, high gain and 0.22 W/kg SAR is proposed in Reference 5. In Reference 6, an ultra-wideband low-specific absorption rate (SAR) metasurface-enabled wearable jeans antenna is discussed for wireless body area network applications. A compact, high gain, wideband antenna for satellite and radar applications has been demonstrated in Reference 7. All these wideband high gain antennas are the popular choices for wireless body area network (WBAN) technologies for mobile health moni- toring and other applications. This paper presents an AMC integrated monopole to achieve high gain over the frequency band from 5.39 to 10.95 GHz for WBAN applications. A 2 × 2 unitcell array AMC with full ground is designed to obtain 90  reflection phase bandwidth from 6.20 to 7.44 GHz (18.56%). The AMC has offered MNG material characteristics in the desig- nated band. The polarization independent behavior of the AMC for TE/TM wave is investigated as the polarization angle, and the angle of incidence vary. The integrated antenna yields S 11 < -10 dB from 5.39 to 10.95 GHz with 92.7%/66.2%/53.9% fractional impedance bandwidth at 6/8.4/10.3 GHz used for C/ITU/X band applications. The air gap of 0.12 λ 0 between antenna and AMC enhances the peak gain up to 10.6 dB. The integrated structure achieves high FBR of 7.3, 18.6, and 9.7 dB at 6/8.4/10.3 GHz. The inte- grated antenna has an efficiency of more than 90% over the entire band. 1-g SAR is suppressed up to 0.203 W/kg at the respective bands which makes it suitable for off-body applications. Received: 17 July 2020 DOI: 10.1002/mop.32756 Microw Opt Technol Lett. 2020;1–6. wileyonlinelibrary.com/journal/mop © 2020 Wiley Periodicals LLC 1